you can also use this nice little php script. i have attached the file popclear.php.txt or you can create your own with the code below

PHP:

<?
#######################################################################
# INFO #
# POPClear allows you to delete all the messages in a POP3 mailbox #
# without downloading or viewing any of the messages. It's perfect #
# for a mailbox you never use that gets nothing but spam. #
# #
# USAGE #
# Requires PHP4. Set the $host, $user, and $pass variables below and #
# execute the script. #
# #
# LICENSE #
# This script is absolutely free. Use at will. The author is not #
# responsible for lost email, blown up servers, or anything else that #
# results from the use of this script. #
#######################################################################